What if a simple test could help predict how long someone with advanced cancer might live? For patients dealing with leptomeningeal disease, a severe complication where cancer spreads to the brain and spinal cord, this question is particularly urgent. Treating this condition is tough, and current methods to assess how well treatment is working are limited. In a recent analysis of multiple studies, scientists found that testing cerebrospinal fluid for circulating tumor DNA can give valuable clues about a patient's condition. They discovered that certain DNA markers in the fluid were associated with worse survival outcomes. For example, patients with specific mutations had significantly shorter survival times. This means that by regularly monitoring these DNA levels, doctors could better tailor treatments based on how the disease is progressing. However, while these findings are promising, more research is needed to standardize how this testing is done and to understand its full potential. For patients, this could mean a future where treatments are more personalized and effective, offering hope in a challenging battle against cancer.
Can a Simple Test in Spinal Fluid Predict Survival for Cancer Patients?
Plain Language Summary
What this means for you:
Testing spinal fluid for tumor DNA could change how we predict and treat advanced cancer, offering new hope. What this means for you:
Testing spinal fluid for tumor DNA could change how we predict and treat advanced cancer, offering new hope. View Original Abstract ↓
PURPOSE: Leptomeningeal disease (LMD) is a devastating complication of advanced solid tumors with limited prognostic and response-assessment tools. Because LMD molecular evolution is frequently compartmentalized behind CNS barriers, cerebrospinal fluid (CSF) circulating tumor DNA (ctDNA) may provide CNS-specific molecular readouts of disease activity. We evaluated whether baseline CSF ctDNA profiles and longitudinal ctDNA kinetics associate with survival in LMD.
METHODS: We performed a systematic review and meta-analysis (PROSPERO CRD420251068543) of Embase, PubMed, Cochrane CENTRAL, WHO ICTRP, ClinicalTrials.gov, Europe PMC, and Web of Science from inception through June 2025. Eligible studies included adults with solid-tumor LMD undergoing anti-cancer therapy with CSF ctDNA assessed at baseline and/or serially and reported associations with overall survival (OS) and/or progression-free survival (PFS). Random-effects models pooled hazard ratios (HRs). Longitudinal studies were analyzed separately due to limited availability.
RESULTS: Fourteen studies (n = 963) evaluated baseline CSF ctDNA and two studies (n = 26) evaluated longitudinal kinetics. Adverse (non-reference) baseline ctDNA status (e.g., EGFR mutation positive vs. negative) was associated with inferior OS (pooled HR 2.40, 95% CI 1.73-3.33; I²=36.6%) and PFS (pooled HR 2.45, 95% CI 1.36-4.44; I²=15.5%). Longitudinally, increasing CSF ctDNA variant allele fraction was associated with worse OS (pooled HR 4.11, 95% CI 1.25-13.48; I²=8.5%). Across longitudinal reports, serial CSF ctDNA measurements tracked progression and response.
CONCLUSION: Baseline and serial CSF ctDNA measurements are associated with survival outcomes in LMD and may complement clinical and radiographic assessment. These findings support prospective, standardized, multi-timepoint CSF ctDNA studies in LMD and warrant CSF-access-enabled monitoring to inform therapeutic adaptation.